class Array
    def gnomesort!
      i, j = 1, 2
      while i < length
        if self[i-1] <= self[i]
          i, j = j, j+1
        else
          self[i-1], self[i] = self[i], self[i-1]
          i -= 1
          if i == 0
            i, j = j, j+1
          end
        end
      end
      self
    end
  end

  
  ary = [7,6,5,9,8,4,3,1,2,0]
  ary.gnomesort!
